This invention relates generally to medical devices for draining fluids from body cavities. More particularly, it relates to an improved vent for positively locating a body cavity that has fluctuating fluid pressure and draining the cavity.
One vent for draining fluids from body cavities, particularly the pleural cavity, is described in U.S. Pat. No. 4,664,660. The vent described in that patent includes a vented housing having a fluid-receiving chamber, an anti-reflux valve mounted to the housing, and a catheter that extends from the housing and is in communication with the chamber through the anti-reflux valve. The apparatus is used by first inserting a solid trocar into the end of the catheter. A skin incision is then prepared and the trocar/catheter assembly is introduced into the pleural space through the incision. When the trocar is removed from the catheter, fluid drains from the pleural cavity through the catheter and the vented housing.
Another apparatus for draining fluids from body cavities, particularly liquids from the pleural cavity, is disclosed in U.S. Pat. No. 4,447,235. The apparatus described in that patent includes a catheter/hollow needle assembly that is inserted into the pleural cavity. During the insertion procedure, a vacuum is maintained in the needle with a syringe. As a result, liquid enters the syringe when the needle enters the pleural space, and can be observed by the surgeon.
U.S. Pat. No. 4,404,924 describes a medical suction device that has an indicator flag to signal the pressure being developed by the device. The indicator flag is designed to stand upright when the pressure in the device is relatively high and to collapse when suction is developed.
U.S. Pat. No. 4,164,938 describes a device for diagnosing the presence of a tension pneumothorax. The device includes a sleeve with a needle at one end for puncturing the chest wall. The needle extends into the pleural cavity and a diaphragm at the other end of the device expands when the pressure in the pleural cavity is greater than atmospheric.
U.S. Pat. Nos. 4,944,724 and 5,356,386 disclose devices used to drain fluids from the pleural cavity. The fluids are drained through a passage that extends from a catheter to a one-way valve. The catheter is inserted with a furrowed trocar that permits fluid communication between the tip of the catheter and an indicator on the device. When the catheter enters a body cavity in which there is fluctuating fluid pressure, the fluctuating pressure causes the indicator to deflect. After the trocar is removed, a seal prevents ambient air from entering the device.
Some physicians feel that using a trocar to introduce a catheter imposes a risk of damaging the heart, lung, or surrounding tissue. This risk can be greatly reduced by using a flexible guide wire for introducing the catheter. However, such guide wires cannot readily be passed through the seal of the devices shown in the U.S. Pat Nos. 4,664,660; 4,944,724; and 5,356,386; patents.
The present invention provides a thoracic vent kit that enables a physician to introduce the thoracic vent over a flexible guide wire. Like some prior vents, the vent has a reservoir and a manifold with an introducing port, a catheter port, and a linear passage extending from the introducing port to the catheter port. It also has a second passage extending from an intersection on the linear passage to an evacuation port. The manifold provides a fluid path that extends from a catheter through the catheter port, a portion of the linear passage, the second passage, the evacuation port, and a one-way valve to the reservoir. A seal is provided on the linear passage between the intersection and the introducing port.
Unlike prior known thoracic vent kits, the present invention may include a removable cannula that is small enough to fit in the catheter, but also has an internal diameter that can accommodate a flexible guide wire. The cannula may have a beveled tip at its distal end, and a luer threaded cap at a proximal end. A removable plug may also be included in the kit. The plug may have a shaft with a chamfer that has a maximum diameter that is greater than the diameter of the linear passage between the intersection and the catheter port, and a terminal dimension that is less than that diameter of the linear passage. The opposite end of the plug may be configured for connecting the plug to the introducing port while the chamfer seals the air path.